The possibility of obtaining wafers and substrates, having a structured surface (“patterned substrate”) that is to say the surface of which is at least partly covered by patterns in relief, can be very advantageous. In particular, this is the case for photovoltaic cells and most optical or optoelectronic devices, namely light-emitting diodes (LEDs) in which the efficiency of conversion of an electric current into light is highly dependent on the surface state of the substrate from which they are manufactured.
The existing methods for structuring substrates comprise numerous steps, a synthetic review of which is reproduced in FIGS. 1a to 1f. 
FIG. 1a illustrates a substrate 100 on which the patterns are to be created. On this basis, the current conventional technique proposes the creation of a layer of hard mask 110 generally made of nitride of silicon of oxide or of silicon. This layer 110 is deposited on a face of the substrate 100, as illustrated in FIG. 1b. One or more patterns 130 are then defined in the layer 110 in such a way as to selectively expose certain portions of the face of the substrate 100 while protecting other portions with the hard mask.
In order to define these patterns 130, as illustrated in FIG. 1c, conventionally the deposition of a layer for defining patterns 120, made of resin, and then the opening of the resin by one of the conventional photolithography techniques are planned.
FIG. 1d and FIG. 1e show, respectively, the opening of the hard mask and the elimination of the layer of resin 120.
At this stage, the substrate 100 can be attacked from its front face via etching in order to define the desired relief.
The illustration given in FIG. 1f is an example of a relief 140 in the shape of an inverted pyramid that can be for example implemented via wet etching using a basic solution (for example containing potassium hydroxide for a material of substrate to be etched such as silicon). Dry etching is also possible but has the disadvantage of being costlier. At the end of etching, the hard mask can be eliminated in order to arrive at the result of FIG. 1g. 
From the figures described above, it is understood that a large number of steps is necessarily comprised in the current techniques that use hard masks. These current techniques thus lead to a method time and a cost that it would be advantageous to reduce.
The goal of the present invention is in particular to at least partly reduce the disadvantages of the current techniques.